No systems are known for the elimination of consequences of the angular clearances in driving gears, especially in those designed for machine tools.
In driving gears loaded with impact or impulse-type moments which appear distinctly, for example, in the milling of particularly narrow shapes with milling heads or face mills, the members of the kinematic chain transmitting the driving torque lose and recover in alternate cycles their mutual contact to this causes noisy operation, quick wear-and-tear of the parts, frequent total failure of the gear, and uneven peripheral velocity of the cutting tool. A non uniform speed of the milling spindle creates disadvantageous operation conditions of the cutting tool, causes quick wear of the cutting edges thereof, results in poor quality of the surface being machined, and increases the susceptibility of the machine tool to self-exciting torsional vibrations of the spindle.